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This is a great question. I asked this myself when I used to play FIFA 99 on PC as an 11 year old kid and went on a 6-year long college journey trying to find an answer to this.Its really complex but let me dumb it down a bit (actually a lot). Let us start right from the bottom:Matter is composed of atoms (we can go smaller than this but this should be enough for this question)Atoms have electrons and flow of these electrons is defined as electricityNow, to make use of these electrons, we create transistors which can store/free electricity as needed. They are stored in units of 1 (5Volts) and 0 (0 Volts)An 8-bit number is then represented with 8 transistors. So 8-bit representation of the number 3 will be : 0000 0011. How is that achieved in hardware? Keep 8 transistors side-by-side (called registers and memory units). Make the first 6 transistors hold 0V and the next 2 transistors hold 5VNow, an organization of such registers and memory makes a cpu+ramTo make it easy to compute using the CPU, we developed machine code. This language is what essentially runs on the CPU. What do I mean by "run"? It means, keep flipping bits. If I want to perform 2+3, in machine, I would store 2 in one register (register explained above) and 3 in another register. Then I would take these values to an Adder unit which would do a mathematical add (not the same as voltage addition) and give me the reply in another register. This is what a sample machine code would look like:80 02 F380 03 F488 F3 F4 F5Obviously, no one understood anything with this. So we came up with an ingenuous system to make it human readable. This is called assembly language. The following piece of code represents the above mentioned numbers:MOVI 2, REG AMOVI 3, REG BADD REG A, REG B, REG C (add A and B and store in C)where MOVI = 80REG A = F3REG B = F4REG C = F5ADD = 88Voila, our first coding language :)Now, assembly is too hard for humans to remember and code properly in. So they developed compilers that would convert a high level language like C to assembly language (remember, this assembly language does the actual flipping of bits)So, a C representation of the above mentioned assembly would be:{int a = 2; b = 3;c = a+b;}Just like people could write poems with English and not with hand signs, we realized that with an expressive language, people could write some better programs. Then compile it to assembly. Then that would flip bits in registers. Which in turn would affect transistors, which affect flow of electronsWith the above found expressiveness, we wrote operating systems to maximize hardware usage, since it was seen that the CPU remained idle while we fetched data from diskEverything from your keyboard input to mouse to desktop to windows to sound is a program written in such expressive languages, running on top of the OSOn the OS, we developed a network stack called TCP/IP. This stack provided a standardized methodology for computers to communicate with each otherOnce that was working and we managed to hook computers to each other using cables, we went on to create WWW and http. This allowed people from different networks to communicate with each other. Note that http is a protocol. Servers and Clients are programs that follow (at least) http in addition to internal protocols.Let's walk the other way, from software to electrons nowWhen you type Google in the browser and hit Enter key, an http request is sent from your browser (the client) to Google (server)In your own computer, the browser is a program written in C/C++This gets compiled to assembly (actually browser is already compiled, you're just giving input numbers to the compiled browser)The operating system (windows/linux etc) and device drivers are all already compiled to assembly and are running on your machineWhen the browser assembly gets it's turn to run on the CPU, it runs the assemblyThis assembly code does flipping of bits in registers and memoryThe registers and memory are composed of transistorsTransistors control the flow of electrons and hence electricity.I've overly simplified it. But this is what it is in essence. There are tons of other things happening but mostly, it's different software programs interacting with each other (remember the movie matrix?).I am glad you asked this question. Computers are man-made miracles of the highest order. No single person could have thought of all this. It has taken more than 50 years and millions of smart people to get to this point. Most computer programmers and professionals I've talked to, have an incomplete picture of what a computer actually is and (as you put it) how does electricity get converted to software.Hope this helps.Edit:Judging by the popularity of this answer, it seems many people would use this as reference somewhere. I would like to point out that I have dumbed it down to the definition of trivia. I have not touched even 1% of the actual detail. Every bullet point I mention has thousands of engineers working on it every day and the details are mind-numbing.The answer has some inaccuracies. For example, it is not true that 1 transistor represents 1 bit. In fact, a group of 6 gates (making a D Flip-flop) that does it. There are other flip-flops doing the same. However, I did not feel like going into details of gates and logic circuits.However, the overview is true. This is essentially how you would see a computer system from the outside.Also note that we have come much further away from this trivial description. I did not even talk about caches, coherencies, consistencies in multiprocessor systems, schedulers, microarchitectures, register files, bridges, GPU, how display works, how does BIOS work, what is init?, what do you mean when you say something is a "program"? etc.Nor did I talk about state machines, ALUs, pipelines, power supply, how current is measured, CLOCK, system ticks, HDLs, control logic, digital circuits like mux/demux, decoders, cryptos etc.That is just too much info to sit and post online (I do have work and social life in the real world ;) ). Also a lot of information on wikipedia about all this seems outdated/trivial.Edit:If *all* of the above seems like outrageously trivial to you, let's grab beer sometime and discuss the current state of Architecture and OS. You are obviously someone who I can learn more from.

In almost any other language, the following statement or some equivalent:main = do  let x = print 3  x  x … will print 3 to the screen once, and leave ‘x’ with some value to confirm the print was successful or null/undefined. It may or may not try to throw an error about executing a number, or even refuse to compile due to syntax errors.In Haskell, this prints 3 twice, because line 2 defines x as the action of printing a 3, and then the action of ‘x’ is actually executed twice. This is why there is literally some argument over whether Haskell is the worst language for procedural logic or actually the best. Defining your own control structures is so trivial that writing a new sub-language to better express and solve your problem is perfectly reasonable even for quite simple problems.In short, not just functions but also actions are values in Haskell, just like the number 3.There are also very, very few languages where the following even makes sense, let alone is useful:loeb x = go where go = fmap ($ go) x This function is hard to even describe to a newbie. But it’s also awesome. It takes some ‘structure’ (literally some structure, it can be an array, a list, a map, another function, literally anything that has a defined Functor instance, and almost everything useful can be a Functor in some way) of values that are functions, and applies each function in the structure to the end result of calling the loeb function, not the input. (Read ($ go) as “applied to go”)You can use it like so:loeb [length, (*2) . (!!0), liftA2 (+) (!!0) (!!1)] What is this gobbledygook?! Well, [ ] means it’s a list of values, length is a function that… computes length.!! is the indexing operator such that [‘a’,’b’,’c’] !! 1 = ‘b’, (!!0) is the indexing operator with it’s second parameter pre-supplied as 0, leaving a 1-argument function that takes a list and gives you the 0th element of that list. (*2) is the multiplication operator pre-supplied with 2, giving a 1-argument function that doubles it’s argument. (*2) . (!!0) is the left to right composition of taking the 0th element of a list and then doubling it.liftA2 (+) takes the addition function (+) which has been given no arguments yet, and “improves” it so it works on things more complicated than Numbers. In this case, it’s being improved to work on functions - so you can just add together functions now, passing the same input to each and then summing the result. In this case, this is a function that will take a list, and return the sum of the 0th and 1st elements.Thus this:loeb [length, (*2) . (!!0), liftA2 (+) (!!0) (!!1)] evaluates to this:[3,6,9] And it does it by reasoning like so:loeb [length, (*2) . (!!0), liftA2 (+) (!!0) (!!1)] Let done = loeb [length, (*2) . (!!0), liftA2 (+) (!!0) (!!1)] [length done, ((*2) . (!!0)) done, (liftA2 (+) (!!0) (!!1)) done] [3, ((*2) . (!!0)) done, (liftA2 (+) (!!0) (!!1)) done] [3, (*2) 3, (liftA2 (+) (!!0) (!!1)) done] [3, 6, (liftA2 (+) (!!0) (!!1)) done] [3, 6, ((!!0) done) + ((!!1) done)] [3, 6, 3 + 6] [3, 6, 9] Note that this is not the only order of reduction, or the one that Haskell is guaranteed to make, it is merely a reduction that is easier to follow. Every reduction order leads to the same result because of Haskell’s insistence on purity, otherwise this would get really hair-raising, really fast.There’s also this gem:newtype Mu f = Mu {out :: f (Mu f)} cata f = f . fmap (cata f) . out You use it like so:data TreeF a f = Node a | Branch f f deriving Functor -- Yes, you can just *ask* for things to be made Functors for you type Tree a = Mu (TreeF a)  treeSize = cata reduce where  reduce (Node _ ) = 1 -- A node has size 1  reduce (Branch left right) = left + right   -- The size of a branch is the sum of the sizes of left and right So just when you’re thinking “Okay, I can handle functional programming, just replace loops with recursion” Haskell goes and abstracts away the recursion itself, leaving only the description of how to handle a single layer of the tree. How it does this, I leave as an exercise for the reader.So really, no, Haskell isn’t like learning to program from scratch, because that’s quite an understatement.Edit: There may or may not be typoes in the code, I have not run it.

Here we go again, eh? Tell you what, since you specifically asked about a MiG-21, we'll do that. If you want a description of your favorite modern fighter, you can ask in a separate question.The MiG-21 is an older third-generation fighter aircraft designed by the Mikoyan-Gurevich design bureau for the Soviet Union. It remains in popular use today for a variety of smaller countries due to its low cost and reliability. It is primarily designed as a high-speed interceptor (carrying guns as well as both infrared-guided and radar-guided missiles), but can also carry bombs and rockets in an air-to-ground role. The variant we'll be discussing today is the MiG-21bis, the most modern incarnation of the MiG-21, with a more powerful engine and improved avionics.So just as before, first we'll talk about the systems of the MiG-21bis before we get into the controls. There's many more systems on a MiG-21 than on a 737, so buckle up and let's dive in.Engine: The MiG-21bis is powered by a single Tumanskiy R25-300 turbojet engine with two-stage afterburning capability, giving the MiG-21 supersonic speed. In order to operate at supersonic speeds, the engine inlet has a movable nosecone that extends as the aircraft speeds up. This keeps the shockwave in front of the inlet. The engine is also protected against compressor surges (situations where a reversal of air pressures causes air to move the wrong direction through the engine, sort of like a backfire) by anti-surge doors that open to restore normal airflow in the engine. Exhaust is routed through a controllable nozzle that opens or closes to maximize engine thrust and smoothness. The engine is started using the battery.Flight controls: In addition to conventional flight controls, the MiG-21bis also has a boundary layer control system (BLC) that provides additional low-speed maneuverability (important given its stubby wings). The effectiveness of the stick in pitch control is managed by the АРУ-3ВМ that increases stick sensitivity as airspeed decreases. A drag chute can be deployed after landing to increase braking. The MiG-21 also has attachments for JATO (jet-assisted takeoff) rockets, though typically no such rockets are installed. The MiG-21 has tricycle landing gear, aerodynamic speed brakes, and three-position flaps on each wing.Electrical system: The MiG-21 has onboard batteries for electrical power. When the engine is running, a DC and AC generator is used to produce electrical power and charge the battery. When the battery is in use, two inverters convert DC to AC power for the systems. Electrical systems are connected to one of three bus bars.Fuel system: The MiG-21 has three internal fuel tanks: one in each wing and a service tank at the engine. It also has provisions to carry up to three drop tanks, one under each wing and one on the fuselage centerline. Fuel from the wing tanks is fed to the service tank using the #1 fuel tank group booster pump. Fuel from drop tanks is fed using the #3 fuel tank group booster pump. The service tank booster pump ensures the engine gets an uninterrupted supply of fuel even during negative-g maneuvering. These three booster pumps are electrically powered.Hydraulic system: The MiG-21 has two hydraulic systems. System #1 boosts the flight controls (elevators and ailerons) giving the pilot more control of the airplane through the yoke, especially at high speeds. System #2 powers everything else: Landing gear, brakes, flaps, speed brakes, engine nozzle, anti-surge doors, and retractable nose cone. System #2 also backs up system #1 in boosting the flight controls.Pressurization and oxygen systems: The MiG-21 cockpit can be pressurized once the canopy is closed. The pilot additionally wears an oxygen mask that can deliver a mixture of pure oxygen and engine bleed air, and protects against biological warfare agents. For extremely high-altitude flight, the airplane can be operated by a pilot wearing a pressure suit.Pneumatic system: Compressed air is used to stop tire rotation after gear retraction. It's also used in conjunction with the hydraulic system to power the brakes and deploy the drag chute.Autopilot: The MiG-21 has an automatic flight control system (AFCS) capable of maintaining heading and altitude as well as offering an automatic landing mode. The autopilot can also be operated in a "stabilization" mode that smooths pilot inputs.Pitot-static system: The MiG-21 measures airspeed and altitude using one of two pitot-static systems (main and auxiliary), which can be heated in icing conditions. Angle of attack is measured using AoA vanes.Communications systems: The MiG-21 has a single UHF-band communications radio, the Р-802Г. The radio cannot be manually tuned; it must be loaded with up to 20 preset channels.Radionavigation systems: The MiG-21 has multiple radionavigation systems. The radionavigation compass (АРК-10) homes in on navigational radio stations (non-directional beacons or NDBs), displaying their bearing to the pilot. The distance interrogator (СОД-57) measures distance to a radio station. The POLYOT-ОИ is a more accurate radionavigation system that allows the aircraft to navigate to omnidirectional navigational beacons (VORs). The POLYOT-ОИ can also perform dead reckoning, receiving a navigation signal and then calculation further positions using the aircraft's known heading and speed. The POLYOT-ОИ can operate in a landing mode, where it provides precise guidance for a descent path to the runway, or in an enroute mode, where it provides guidance to enroute navigational signals (and optionally a planned descent to a desired altitude).Radar system: The MiG-21 has a forward-looking air-to-air radar capable of detecting and tracking aircraft, and guiding missiles against those aircraft. The radar has anti-jam capability and ground/cloud filtering capability. The radar can operate in three modes: a scanning mode, a tracking mode where it tracks a single target after lock-on, and a fixed-beam mode where it fixes the beam straight ahead for measuring distances. The MiG-21 also has a radio altimeter that points downward, measuring height above the surface.RWR system: The MiG-21 has a radar warning receiver that detects incoming radar signals in all directions and displays them to the pilot, along with an audible tone.Interrogation system: The MiG-21 has a СРЗО-2 IFF (identify friend-foe) transponder that interrogates other aircraft, expecting the correct coded response. It has a СОД-57 transponder for use with air traffic controllers.Weapons system: The MiG-21 has an internally-mounted 23-mm cannon. Its two barrels are loaded using a primer charge. The MiG-21 also has four pylons on which weapons can be mounted, including: radar-guided missiles, heat-seeking missiles, unguided rockets, incendiary tanks, bombs of many varieties (high-explosive, anti-armor, illumination, cluster, etc.), and drop tanks.Targeting system: The MiG-21 has a collimated optical sight that operates in two modes: In the gyro mode, the system uses a gyroscope to calculate lead, and places the pipper where it estimates cannon rounds will land when fired. In order to make this calculation, the pilot must select the wingspan of the aircraft he is attempting to attack. In the missile mode, the gyro places the pipper over the aircraft the next missile will track.Exhausted yet? It's time to begin going through the switches. Let's go from left to right, starting with the left-hand side cockpit wall.The metallic placard at the very back, near the seat, is the УК-2М amplifier for the comm radio. These switches select which microphone to listen to the pilot on. The far switch (М-Л) toggles between using the normal microphone (микрофон) and the throat microphone (ларингофон; used when wearing a pressure suit). The near switch (КМ-ГШ) toggles audio between the oxygen mask (кислородная) and pressure suit helmet (гермошлем).Along the sidewall, the larger switch placarded "MAX-MIN" is the АД-6Е pressure control switch. This system provides air pressure to the anti-g suit, which inflates when during high g to help keep the pilot conscious. In the "MAX" position, maximum air pressure is available to the suit. In the "MIN" position, no air pressure is available to the suit. (You would use this position when wearing a pressure suit instead of an anti-g suit.)The BUS Nr. 1 switch turns on power to the #1 electrical bus bar.The ENGINE OXYGEN FEED SYSTEM gauge displays available air pressure for engine starting (must be around 10 kg/sq. cm). Adjacent the gauge are the engine starter controls. The ENGINE STARTER button initiates an automatic engine start. The COLD START - NORMAL START switch toggles between a normal engine start and a cold crank. A cold crank is when the engine is run on battery power but no fuel is introduced (so no start occurs). It's used to vent excess fuel vapor from the engine in the event of a false start.The smaller MAX-MIN switch underneath the sidewall extrusion controls pressure suit pressure.On the console, there are three colored switches that control the oxygen system. The 100% OXYGEN toggles between 100% oxygen and a normal air mixture of nitrogen and oxygen. (100% oxygen is used in emergencies and at higher altitudes.) The EMERGENCY OXYGEN switch toggles the emergency oxygen supply. The HELMET VENT switch turns on pressure suit helmet ventilation.Back up to the top and further rightward, the FLIGHT SUIT VENTILATION knob controls the amount of cooled ventilation air provided to the flight suit.The panel underneath this knob is wide and contains a variety of controls. The SEAT UP-DOWN switch raises and lowers the seat. The AUX 2-POS NOZZLE CTRL switch is used if the normal exhaust nozzle control system fails. This auxiliary system can move the exhaust nozzle between two preset positions, fully open and fully closed. The AUTO-COLD-WARM switch controls the temperature of ventilation air. The SPS switch toggles on or off the boundary layer control (BLC) system. The IDENT button performs an ATC identification function on the СОД-57 transponder, which highlights this aircraft on air traffic controller radar. The MISSILE SOUND knob controls the volume of the missile tone that informs the pilot whether a heat-seeking missile has a good lock. The AUTO-MANUAL switch controls the operation of the АРУ-3ВМ system that controls stick sensitivity. Normally sensitivity is automatically decreased as speed increases, but it can be manually controlled as well. The next right switch (label obscured) increases or decreases stick sensitivity when the АРУ-3ВМ is in manual mode.Back leftwards to the next lower panel, the guarded E. NOZZLE switch controls operation of the compressor anti-surge doors (auto or manual). Likewise, the CONE switch toggles between auto or manual operation of the nosecone retraction. The HELMET HEAT FAST button quickly heats the pressure suit helmet visor to defog it. The AUTO switch toggles automatic helmet heat. Lastly, the RSBN-ARC switch toggles the NPP between displaying navigation data from the АРК-10 (ARC) and the POLYOT-ОИ (RSBN). The NPP is discussed later.Below, the guarded DROP CHUTE button jettisons the drag chute after landing.The gray panel next to the throttle is the POLYOT-ОИ control panel. The knob at top-left controls the volume of the navigation signal (which can be heard as a morse code station identifier). The pair of green lights at the top illuminate when an azimuth and distance information are being received (respectively). If those lights extinguish, the POLYOT-ОИ reverts to dead-reckoning mode. Any cumulative errors introduced during dead reckoning calculations can be corrected using the two switches at the top-right of the panel (DIST and BRG). These switches are used when the pilot overflies a landmark with a known bearing and distance to a navigational station. The two large knobs in the center set the navigation radio channel and landing radio channel. Channel number is displayed in each window. The button in the bottom left resets the azimuth correction.The black panel below is the flap control panel. The three toggle buttons move the flaps between up, takeoff, and landing settings. The small silver button resets the flap buttons in the event that the flap setting and flap buttons get out of sync.Moving right, we have the throttle, which sets engine power. The hinged gate at the aft end of the throttle track is the idle stop. To move the throttle past idle and shut down the engine, this gate must first be lifted. There is another, similar gate on the throttle lever itself that is used to move the throttle out of the cutoff position when starting the engine. The lever beneath the throttle is the friction lever and controls throttle stickiness. The red guarded button jettisons the JATO rockets following a jet-assisted takeoff. The throttle lever itself rotates forward and backwards; this is used to move the radar cursors up and down (discussed later). The red button on the throttle is the push-to-talk switch, used to talk over the radio.Back up above the throttle track we have various engine controls. The recessed black button deploys the drag chute.The AD CHECK button performs a test of the POLYOT-ОИ. (When held, the NPP should display a distance of 291 km and bearing of 177°, as the label says.) The AUTO GEAR BRAKE switch toggles the anti-skid unit. The A/B ON switch activates the afterburner system, allowing the engine to use afterburners. The AIR RELIGHT switch is used to attempt an in-air engine relight in the event of an in-flight flameout. The ENG APU switch provides power to the engine starting unit, which starts the engine. The FIRE EXT switch powers the engine fire extinguisher system.The canopy rod above these controls can be moved and secured so as to hold the canopy open on the ground.Let's move forward to the left-hand corner section.Ahead of the throttle, we have a pilot oxygen supply quantity gauge (top, measured in liters). Below that, the FIRE EXT button activates the fire extinguisher. Below that button is the pilot oxygen pressure gauge.There's a panel of two switches just ahead of the throttle. The AILERON BOOSTER switch activates the hydraulic booster that increases the stick's ability to move the flight surfaces (think power steering). The SECOND REHEAT switch activates the second-stage afterburner (think rocket launcher).At the top of this corner section are two red canopy knobs. The larger knob locks the canopy and the smaller knob pressurizes it. When the canopy is unlocked, the small red disc light above the levers illuminates.To the right of the O2 quantity gauge is a three-position switch that toggles landing lights, taxi lights, or both off.To the right of that is the landing gear lever. It has three positions: up, down, and neutral. The neutral position holds the gear where it is. A locking pin on the top prevents the gear from being retracted accidentally on the ground. The pilot must move this pin out before the lever can be moved up.Below the gear lever are the gear and flap lights. The three green lights indicate that the landing gear is down and locked. The three red lights illuminate when the gear is up. The FLAPS OUT light is illuminated when flaps are deployed. The light below it illuminates when the speed brakes are deployed. The red light on the left side illuminates if the flaps are lowered but the gear is not, to remind the pilot to lower the gear. The knob controls display brightness for night operation.Ahead of the aileron booster controls is the autopilot control panel. This control panel consists of four lights that indicate which autopilot mode is active (LANDING DIRECT [provides landing guidance], LANDING AUTO [auto-land], STAB [stabilize and smooth pilot inputs], or RECOVER [recover the aircraft to level flight]). The ALT MODE switch activates an automatic low-altitude recovery mode that will cause the autopilot to intervene if the airplane gets too low. The CANCEL button disables the autopilot.Now let's handle the forward panel, with the main flight controls:The top-left portion of the main panel controls the weapons systems. The READY light indicates that the cannon is armed and loaded. The MASTER AIR-GND switch toggles the optical sight from air-to-air mode to ground bombing mode. The IR-NEUT-SAR switch toggles between firing infrared-guided missiles and semi-active radar-homing missiles. The large dial in the center chooses which missiles, rockets, or bombs to fire. You choose the weapon type using the outer labels, and the pylon you want to fire from with the inner label. The MiG-21 has four pylons, numbered 1-3-4-2 (left to right). The RELOADING buttons each fire an explosive charge that clears a jam and reloads the cannons. You can reload a jammed cannon up to 3 times.Moving right, the top dial is the nosecone position indicator. Normally the nosecone is automatically controlled, but when in manual control mode, the small dial to the bottom-left is used to manually set nosecone position.The hollow dial indicates the selected manual nosecone position. The dial below it is the АРУ-3ВМ setting (pitch sensitivity setting). The outer scale indicates aircraft speed and the inner scale indicates altitude. The needle indicates pitch sensitivity. If the АРУ-3ВМ is operating properly, the needle should roughly match the airplane's current speed and altitude.The CANOPY DE-ICE handle is pulled out to enable warm deice air on the canopy. The tadpole-shaped handle is labeled N. GEAR BRAKE and sets the nosewheel brake to either taxi or takeoff settings (to prevent overcontrolling during takeoff). The PROCEED-NAVIG-LDG switch sets the POLYOT-ОИ navigation mode. In PROCEED (descent) mode, the NPP will provide vertical guidance for a descent from the current altitude to a desired altitude, and lateral guidance for the selected RSBN navigation station. In NAVIG mode, the NPP will provide lateral guidance for the selected RSBN navigation station, and constant-altitude vertical guidance. In LDG (landing) mode, lateral and vertical guidance will come from the selected RSBN landing station, which will guide the aircraft to the runway.Moving right we have the controls for the АСП-ПФД optical sight. The two red lights at the top, on either side, are the LNCH (launch) and BREAK lights. The left light illuminates when in weapons range. The right light illuminates when distance is too close and the pilot should break off.Moving to the switches below the LNCH light: The GUN-LNC switch toggles the aiming mode between firing the gun or launching missiles. The S-B switch toggles the pipper symbology between firing missiles/guns ("s"hooting) or dropping bombs. In bombs mode, the pipper helps you time your bomb drop so that the bombs strike their target accurately. The AUT-MAN switch toggles between automatically calculating range data using the radar, or using manually-calculated range data with the help of the target size dial.The scale to the right of the LNCH light is the missile range scale. The pilot references this for range to target when firing missiles. Below we have the target size/wingspan dial. This sets the estimated size of the target. The pilot then uses the throttle knob to resize the pipper until it just fills the target. By knowing the target's size and its apparent size on the canopy, the АСП-ПФД can estimate the range to the target without the radar.Below that is the MISSILE-GYRO lever. In the GYRO position, the pipper is more accurate but jumpier and harder to aim (suitable for attacks on slow or stationary targets). In the MISSILE mode, fewer parameters are used in the pipper calculation, making it more stable but less accurate (suitable for maneuvering attacks).The vertical dial under that switch sets the illumination level of the distance scales. The dial underneath that dial sets the illumination level of the fixed net. The fixed net is a non-moving gunsight that can be used as a backup to the pipper.In the center top, we have two more range indicators with four range scales each. Which scale the pilot reads off the needle depends on what the pilot is firing. The bottom scale is for A/G rockets and guns, middle-bottom is A/A missiles, middle-top is A/A guns, and top is pipper diameter in millirads.Along the right, first we have the ANGLE scale and knob. The knob is marked for different weapon types. The pilot chooses the angular correction appropriate for the current weapon.Below that we have a knob labeled RETICLE; this sets the pipper illumination level. Below that is a switch which toggles the pipper on and off.The three green lights to the right of the sight controls indicate a missile lock. The top light comes on if a K-5MS on the left wing has a lock, and the middle light if one on the right wing has a lock. The bottom light comes on if an R-60 has a lock.To the right of the optical sight are additional indicators. At the top-left is the radar warning receiver (RWR), which warns the pilot of incoming radar signals. The four lights illuminate if a radar signal is detected in that direction. The yellow lights are for daytime operation and the red lights for night operation. The button on the airplane face performs a self-test. The RWR VOL knob controls the volume of the RWR warning tone. The ЗВУКА НЕТ label illuminates when the audio warning system fails.The ATC RESP light illuminates any time the transponder receives an interrogation signal.The bottom left dial is the g meter, and indicates positive and negative g. The red bugs record maximum positive and negative g, and the small button resets the bugs to 1 g.The bottom right dial is the angle of attack indicator. The yellow area is the desired landing angle of attack, and the red area is the danger area approaching a stall.The handle at the bottom right toggles between the main and auxiliary pitot systems.Moving back to the left side, let's handle the first column of flight instruments. The red handle is the emergency brake. The DANGER ALT light illuminates when below the danger altitude, which is a minimum altitude set by the pilot on the radar altimeter.The top dial is the airspeed indicator. Below that is the altimeter. The small window at the bottom of the altimeter is used to calibrate it to sea-level pressure. The knob to the bottom-right sets the sea-level pressure in the window (currently 976 millibars). The bottom dial is the radar altimeter.Moving right to the next two column of flight instruments: The OUTER-INNER switch sets which NDB the pilot is navigating to when using the АРК-10 radio. In Russia, NDBs are placed in pairs leading to a runway. The pilot navigates to the outer NDB, then from there to the inner NDB. In going from the outer to the inner, the pilot has aligned himself with the runway. (Though the outer and inner beacons have different frequencies, the pilot need only tune one, and the АРК-10 will know the frequency of the other.)The red button light is the master warning light. Pressing it acknowledges the warning. The JETT WING TANKS button jettisons the drop tanks on the wing. The FDS button slaves the NPP (discussed later) to the magnetic compass. Holding it down causes the NPP to rotate until its heading matches with the magnetic compass. This should be done periodically, as the NPP is gyro-powered and could drift over time.The top left instrument is the KPP, or attitude indicator. It's a pictorial representation of the sky and ground with a drawing of your airplane. It helps the pilot visualize the airplane's attitude. There are bank scales on the left and right side in degrees, and pitch scales on the face. On the top and right side are horizontal and vertical deviation scales for the POLYOT-ОИ when in landing mode. Keeping the yellow needles centered in the circle will keep the pilot on the proper path to the runway. Similarly, the two yellow bars in the center of the display give the pilot guidance to intercept and maintain a desired course set on the NPP (discussed below). Keeping the bars centered will keep the airplane on course. The red light illuminates when the instrument is caged, to prevent the attitude gyro from tumbling. The dial on the bottom right is sued to raise or lower the airplane index. This is done on the ground to level the KPP. The small ball and track below the KPP is the slip indicator; the pilot uses the rudder to keep the ball centered during coordinated turns.Below is the NPP, or horizontal situation indicator. This instrument is a gyroscopic compass. The pilot turns the bottom-right "ЗК" knob to set the desired course (hollow needle). The middle section of the needle then deflects left or right when the pilot is right or left of course, respectively. The circular needle points towards the station. In the center of the dial is another POLYOT-ОИ landing deviation indicator like the one on the KPP. There are also "К" (course) and "Г" (glideslope) flags that turn white if no course or glide path guidance is being received. The numeric labels around the outside of the inner dial are used by the pilot to fly what's called a "big box" pattern around the airport.Below the NPP is a panel of three controls. The left switch toggles radar-guided missiles between training and wartime modes. The middle screw-knob sets the radar screen gain. The right button degausses the radar display. (Anyone remember degaussing?!)The rightmost column of instruments starts at the top with the vertical speed and bank indicator. The horizontal needle indicates climb or descent speed. The yellow vertical needle indicates rate of turn.Below that is the mach speed indicator, up to mach 3. Then we have a clock with sweep secondhand and time-of-flight gauge. The red button starts and resets the stopwatch, and an unseen silver button on the other side sets the clock.Moving to the center, we have the large and all-important radar screen. The horizontal lines are the cursor; the pilot moves them up and down with the throttle twist-grip. Radar targets appear as small icons on the screen. The pilot places the cursor over a target and presses a lock-on button on the stick to lock onto that target.The array of circular buttons above toggle different radar modes. From left to right, top to bottom: The CONT button turns on anti-jam capabilities for continuous radar jamming, the INTER button for intermittent jamming, and the PAS button for passive jamming. The WEAT button turns on cloud and rain filtering. The IFF button performs an IFF interrogation and displays the results on the radar screen. The LST button turns on low-speed target mode for engaging helicopters or UAVs. The SELFTEST button performs a display test. The RESET button turns off all anti-jam and weather modes.Below the radar are two guarded jettison switches, which jettison the outboard and inboard pylons, respectively.To the right of the radar, at the top we have a distance scale for measuring distance to navigational beacons. Below that is the engine RPM gauge, with two needles. These show the speed of the stage-1 and stage-2 compressors as a percentage of maximum engine RPM. The light to the left illuminates when oil pressure is low. Below the RPM gauge is the exhaust gas temperature gauge. To the left of that is the first bank of caution lights. The top light activates when crossing a marker beacon. (These beacons are placed along approach paths at specific altitudes on the glide path.) The next one down illuminates when the nosecone is extended. The third light illuminates when the BLC is in landing mode. The bottom light illuminates when the aircraft is in trim for takeoff (trim is discussed later).To the left of the caution lights is a button that cages the gyros powering the KPP/NPP, radar, and autopilot. Below that are the hydraulic pressure gauges for the #1 and #2 systems. To the right of that is the fuel quantity gauge. The small dial is used to set the fuel quantity after a refuel.If we move the stick out of the way we can get a look at the lower pedestal. Let's start with the stick itself. The rectangular switch in the center is the pitch trim. The pilot trims the aircraft until it flies level hands-off. The red button disengages the autopilot. The button to the right of the trim engages the autopilot in recovery mode. The small button below the trim attempts a radar lock at whatever is under the radar cursors. There's also a trigger on the back side of the stick for firing guns, and a pickle button on the left side for missiles and bombs. There's a lever at the base of the stick that activates the wheel brakes. A button at the base of the stick drops the centerline tank.Moving down the pedestal, starting from top left, the guarded red button is the emergency A/A missiles jettison button. The TACT DROP switch to the right arms the bombs. The PITOT.CLK.MIRROR HEAT switch activates anti-ice and defog heat for the pitot tube, clock, and periscope mirror. The EMER PITOT switch activates pitot heat for the auxiliary pitot tube.Below and left is the oil pressure gauge. Then we have a bank of 12 lights. The first column of four activate when each of four potential rocket pods is expended. (A pod carries multiple rockets and can be loaded on any of the four pylons.) The middle top light illuminates when the wing drop tanks are empty and the top right light when the centerline tank is attached (not jettisoned). The four lights making up the right two columns and middle two rows indicate which of the four pylons have weapons/tanks attached. The bottom right two lights indicate which of the JATO attachment points have JATO rockets attached. Each bank of lights has a dimmer knob.Down and left is the danger altitude selector. The pilot selects an altitude with this dial and will receive a warning if he descends below it. If desired, the autopilot can recover automatically below this altitude.To the right is the battery capacity gauge. Below the danger altitude selector is the cockpit air pressure gauge, and to the right of that is the wheel brake pneumatic air pressure gauge.The red handles, if you couldn't guess, send the pilot on a parachute ride.Moving to the right-hand corner, we have the large bank of caution lights. Left to right, top to bottom: "abort ignition" light, service tank empty, stage-1 afterburner liit, stage-2 afterburner lit, DC generator failure, AC generator failure, engine fire, exhaust nozzle open, #2 hydraulic pressure low, #1 hydraulic pressure low.Below that another bank of lights: centerline tank empty, wing tanks empty, 450L of fuel remaining, and both wing drop tanks empty.At the top is the emergency gear extension valve, which dumps hydraulic pressure for a manual gear extension in the event of a #2 hydraulic system failure. To the right of that is the dimmer knob for the main cockpit light.Below is a row of switches. The ATC switch powers on the СОД-57 transponder. The WAVES switch selects between one of three pre-programmed transponder channels to transmit over. The TYP.81 switch powers the IFF system. The RWR switch powers the RWR. The ANT-COMP switch toggles the АРК-10 between navigating to a signal (COMP) or letting the pilot listen to the audio (ANT).Moving down, the ARC VOLUME knob sets the volume of the АРК-10 audio signal. The ATC IDENT button is pressed when the pilot wishes to acknowledge an instruction from ATC. The GUIDANCE dial sets the operating mode of the СОД-57. (I'm not entirely sure exactly what it does.)Below that is a black panel containing the radar control switches. The red light indicates a radar fault. The switch below it turns off the radar, places it in standby mode, or activates the radar. The radar has only 15 minutes of coolant available, so it's important to use standby mode as necessary to extend its useful life during a mission. The LOW ALT switch and light toggles a low altitude mode that rejects ground clutter better. The LOCKED BEAM switch puts the radar into locked-beam mode. In this mode the radar does not scan the sky, but simply measures the distance to anything directly in front of it. This is used for ranging operations such as aerial gunnery.To the right is the АРК-10 channel selector. The pilot chooses from one of 9 preset frequencies to navigate to. The SWITCH CNTRL button on the top is used to transfer control to the cockpit from an АРК-10 control panel in the nosecone (used by ground crew).On to the right cockpit section … almost done!Just to the right of the АРК-10 controls are the comm radio controls. The volume knob controls the comm radio volume. The RADIO-COMP switch toggles between navigating to the АРК-10 signal (COMP) or the comm radio signal (useful if you want to find your way to a control tower you're talking to). (This of course requires that the ARC-RSBN switch on the left side be in ARC.) The SQL switch toggles squelch, which removes static noise from the radio signal.Below we have the radio tuner. The red knob selects a preset radio frequency, which appears in the window.On the bottom console we have our red floodlight dimmer switch and the pressure gauge for the main air system.To the right we have a large bank of power switches. For the top row: The CONE switch powers the automatic nosecone position system. PUMP UNIT turns on the hydraulic pumps. TRIM SYSTEM turns on the aircraft trim system.Next row: RADIO powers the comm radio, and ARC the АРК-10. RAD ALT powers the radio altimeter, and RSBN the POLYOT-ОИ. FDS powers the KPP and NPP, AP powers the autopilot, and AP PITCH powers the autopilot pitch channel.Third row: IR/SARH HEAT turns on missile heat (missiles require hot air from the airplane). MSL RKT LNCH is the arming switch that allows missile and rocket launching. PYLON 1-2 PWR and PYLON 3-4 PWR power the outboard and inbound pylon pairs. The NORMAL-DIM-BRIGHT switch sets the intensity of the exterior formation lights. The FLIGHT REC switch turns on the flight data recorder.Bottom row: The GUN switch powers the cannon, and the SIGHT switch powers the АСП-ПФД. The CAM switch powers the gun camera, and the SRZO switch powers the СРЗО-2 IFF system.Adjacent these power switches is the СРЗО-2 IFF system. The center knob selects an IFF channel to transmit on, with the window displaying the selection. The three lights to the left indicate (top to bottom) when the IFF is transmitting, when it's receiving a code, and when it's deciphering a code. The panel at the top right is the IFF self-destruct control. The guarded button at the bottom in real life is labeled "ВЗРЫВ" ("EXPLOSION") and destroys the IFF system. Not sure what the top switch does, but its label in original Russian is "БЕДСТВИЕ" which means "DISASTER". Really cheerful panel here.Moving down to the console, we have another giant panel of switches.The top row (appears as a column from this angle) starts with the NO. 1 and NO. 3 GR. FUEL PUMP switches. These switches power the #1 and #3 fuel booster pumps. Then we have the DSIP. TK FUEL PUMP switch which powers the service tank booster pump.The next row starts with the GYRO FDS AP RDR SIGNAL switch, which powers the gyro for the NPP, autopilot, radar, and СРЗО-2 transponder. To its right, the GYRO FDS DA-200 RDR ATC SIGNAL switch powers the gyro for the KPP, autopilot stabilization mode, rate of turn indicator, СОД-57 transponder, and alternate radar gyro.The red AUX INVERTER is used when the #1 inverter fails. It switches systems normally powered by the #1 inverter to the #2 inverter.The BATTERY GROUND POWER switch turns on the battery and activates external ground DC power (if available). This is typically the first switch you flip in the cockpit. The DC GEN = switch activates the DC generator. Below it, the AC GEN ~ GND PWR switch activates the AC generator and external ground AC power (if available). (They include the = and ~ symbols in case you forget when AC and DC power look like.)The JATO START SYS switch powers the JATO system, and the JATO JETT SYS switch powers the JATO jettison system.To the rear of these switches is the DASHBOARD LIGHT dimmer, which dims the dashboard instrument lights.The BU-45 BOOST SYSTEM DETACH button jettisons the JATO rockets (if attached).Moving further rearward, we have the CONSOLE LIGHT dimmer switch, which dims the backlighting for the control labels. The PBU-1 and PBU-2 buttons activate the video preamp circuits, which are used to test indicator lights. The guarded button to the rear of that runs a check of the СОД-57 system. Then you have a generator voltage adjustment point.Moving upward, we have our final bank of switches. These are the circuit breakers that provide power to, and protect, the various systems. You can read the labels if you want to learn what each switch does. A couple of notes: They call the boundary layer control system "SPS", and the anti-surge shutters "nosecone spilldoors".I will point out the BUS Nr.3 switch on the middle right, which powers the #3 electrical bus bar. It's the counterpart to the BUS Nr.1 switch we started with on the left side of the cockpit, oh so long ago before you realized what you were getting into.The bottom 3 switches are worth pointing out as well. The first two are the ПО-750 start switches that power the #1 and #2 inverters. The third is the battery heat switch. The red knobs are additional circuit breakers for the avionics equipment in the plane.That about does it for the cockpit of the MiG-21bis! I hope you've enjoyed this journey, and I look forward to the next airplane. (Though I need a break to rest my fingers first.)